The present invention relates generally to the field of arc welding systems, and more particularly to an arc welding torch adapted to receive a cylindrical metal electrode.
TIG (Tungsten Inert Gas) welding (also known as gas tungsten arc welding, GTAW, or HELIARC) is a type of arc welding process in which an electric arc is maintained between a cylindrical metal electrode and a metal object. The heat generated by the arc produces localized melting of the metal object. The electrode, typically tungsten, is secured to a torch to enable a user to direct the electrode and establish the point of contact between the electrode and the object. TIG welding may be performed with or without the addition of a filler metal. Typically, the weld puddle and the area surrounding the weld puddle are protected from the atmosphere by an inert gas. The inert gas prevents rapid oxidation of the weld and the surrounding metal.
The electricity for the welding process is provided by a power source through a welding cable coupled to the torch. Typically, the power source is a constant voltage AC, DC, or a combination AC/DC source. In addition, a TIG welding cable typically is adapted to transport the inert gas to the torch. Furthermore, the TIG welding process typically generates a substantial amount of heat in the electrode. Consequently, cooling fluid may be used to cool the torch. Thus, a welding cable for a TIG welding system may transport electricity, gas, and cooling fluid.
The electrodes used in TIG welding typically are shaped like long, cylindrical, metal rods. A typical TIG welding electrode may be secured to a TIG welding torch by a collet, a backcap, and a gas lens. Gas lenses are adapted to provide better gas flow characteristics than collet bodies, another device used to secure electrodes to a TIG welding torch. Gas lenses typically have screens disposed therein to slow down and smooth the flow of gas flowing through the gas lens. To secure the electrode to the welding torch, the electrode is inserted through the collet and gas lens. The gas lens is threaded into a front portion of a threaded torch head disposed within the torch body. The backcap is threaded onto the rear portion of the torch head. As the backcap is threaded onto the torch head, the backcap drives the collet against the interior of the gas lens. The collet is adapted to pinch down on the electrode as the collet is driven against an interior surface of the gas lens, thereby securing the electrode to the torch. In addition, a typical gas lens is adapted to enable gas to flow through the gas lens. A nozzle may be used to direct the gas from the gas lens to the object to be welded.
There are a number of problems associated with the use of conventional collets and gas lenses to secure an electrode to a welding torch. One problem is that the collet and gas lens may be misaligned during installation of the electrode. The misalignment may result in non-uniform gas flow through the gas lens. In addition, a typical collet is small and may easily be dropped during installation, especially in windy conditions. Furthermore, for each diameter of electrode there is an appropriately sized collet and gas lens. Therefore, both the correct collet and gas lens must be selected by a user for each installation of an electrode, thereby increasing the difficulty of installing electrodes in the welding torch, especially when changing one electrode with an electrode having a different diameter.
A need exists for a technique to enable an electrode to be installed in a welding torch more easily than with a separate collet and gas lens. More specifically, a need exists for a system to enable an electrode to be secured to a welding torch using fewer parts and which does not require multiple parts for each diameter of electrode. In addition, there is a need for a device that secures an electrode to a welding torch and provides consistent shielding gas flow.